TIIH ANATOMY OK M KUAI.ATKACTUS — KKSTKVKN. 435 



other species, filled with connective tissue, anion;;j and attaclied to 

 which were the numerous fhie muscle strands which retained the 

 proboscis sheath in position. 



The nerve rini,' is situated at the cxtrcine anterior end of the 

 body cavity, almost under, but sli^htly Ijehind, the orifice of the 

 proboscis sheath. T\w pedal ganglia are not imbedded in the 

 tissues of the foot, but lie just on the surface of the floor of the 

 cavity. The most noticeable feature is, as in related genera, the 

 fusion, not only of ganglia, liut also of their commissures. 



The cerebral ganylia and their commissure (ce. g.) are fused 

 into one loop, on the left hand side the cerebro-pedal commissure 

 also enters into the composition of the ''loop." This "cerebral 

 loop " is placed somewhat diagonally ; on the left hand side it is 

 attached to the pedal ganglion of that} side, and here it has the 

 corresponding cerebro-pleural and pleuro-pedal commissures fused 

 ■svith it (c. pi. pel. com.). On the right side it is fused with the 

 corresponding pleural ganglion, and gives oft" a pedal commissure 

 which is fused with the pleuro-pedal commissure of this side for 

 the greater part of its length (c. ^;c/. com.) 



The left pleural (janyliou (I. pi. (/.) is represented b}' a short 

 stout cord, which, as already stated, is fused at its base with the 

 cerebral loop and pedal ganglion, this basal portion being the 

 fused cerebro-pleural, pleuro-pedal, and cerebro-pedal commissures. 

 At its distal end this cord is slighty constricted, and then swells 

 into the sub-intestinal ganglion. The right j^leural ganglion (r. 

 pi. g.) is rather better differentiated from its pedal commissure 

 (pi. pd. com.), but is intimately fused with the cerebral loop on 

 this side ; it may, however, be distinguished from it to a certain 

 extent by a depression between the two on the inner side of the 

 ring. The commissure which connects this with the supra-intes- 

 tinal ganglion, although short, is well differentiated from both 

 ganglia. 



The pedal ganglia {p>d. g.) are large, and, as usual, give off a 

 multitude of nerves to the foot, the largest pair of which are 

 metapodial nerves, springing from the inner, mesial side of each 

 ganglion. The various pedal commissures have already been 

 described. 



The sub-intestinal ganglion {sb. int. g.) is, as already stated, but 

 a differentiated portion of the left pleural ganglion ; it is attached 

 by a very short commissure to the right cerebral ganglion. There 

 is thus a condition of zygoneury on the right side. 



The supra-intestinal (sp. int. g.) is a well-defined oval ganglion 

 attached by a short commissure to the right cerebral ganglion. 



The buccal ganglia are situated below the cesophagus, in the 

 angle formed by its insertion into the buccal cavity; the buccal 

 commissure Avas not found. 



The visceral ganglia were not found. 



